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METHODICAL SERIES EXPERIMENTS ON CYLINDRICAL BOWS

Experiments were carried out with models of 0.800, 0.825 and 0.850 block coefficient, for which three cylindrical bow variations of a parent conventional bow form were made for each block coefficient and their effect on resistance and propulsion factors determined. The results show that for a 600 ft ship of 0.800 block coefficient operating at speeds up to 15 knots loaded a cylindrical bow has little to be recommended. At 0.825 block for ships of 600 ft a reduction of about 10% in required power can be expected from a cylindrical bow at 15 knots loaded and of about 6% in ballast at corresponding speed of 16 knots. For 800 ft ships operating at 16 knots loaded and at 17.5 knots in ballast the reductions are 9 and 10% in the loaded condition for 0.825 and 0.850 block coefficients respectively. The reductions in ballast for these ships are very small for the 0.825 block coefficient and for the 0.850 block ships even a slight increase in required power is found with the cylindrical bow. The highest reductions in required power with a cylindrical bow are thus obtained with ships of 0.825 to 0.850 block coefficients in the loaded condition. For these blocks a cylindrical bow can definitely be recommended, since ships so fitted have already proved that no adverse effects are to be expected with regard to seakeeping or course stability.